Textile construction

ABSTRACT

A fitted sheet for a mattress comprises a rectangular panel of knit material having a central rectangular area extending from one end of said panel to the other end thereof. Side margins flank the central area, and folded under said central area and joined thereto by seams extending across each end of the central rectangular area. The sheet is characterized in that the seams at each end of said central rectangular area are arcuate.

FIELD OF THE INVENTION

[0001] The present invention relates to the field of fitted bed sheets. In particular, the present invention relates to certain improvements in fitted sheets.

BACKGROUND OF THE INVENTION

[0002] The present applicant is the inventor of the fitted bed sheet described and claimed in U.S. Pat. No. 5,765,241. That sheet, which is fabricated from knit material, is known in the trade as an envelope sheet. It is made from a tube of knit fabric, slit along an edge to form a rectangle. The side margins of the rectangle are then folded inwardly to the midline of the sheet, and top and bottom edges are sewn, joining the top and bottom edges of the folded-over margins to the top and bottom edges of the sheet of fabric. The inwardly directed edges of the margins are then finished with binding in a continuous loop to finish the sheet. The advantages of such a sheet are that it is economical to manufacture, and it fits securely on a mattress, especially a multi-position hospital mattress, without coming off. It lays flat on the mattress, even when the mattress is articulated, which results in a comfortable surface that does not have wrinkles on it to promote bed sores.

[0003] The applicant has identified two areas of potential improvement in the envelope sheet. First, the sewing of the top and bottom edges of the folded-over sheet is substantially transverse to the longitudinal axis of the sheet. This does tend to create “ears” of material at the outer edge of the sheet when it is placed on a mattress. These ears tend to be positioned on the side surface of a mattress, near the corners of same. They are untidy looking, and a waste of material. That is, they create the appearance of an ill-fitting sheet.

[0004] The other area of improvement lies in the binding that is sewn in a continuous loop around the inward facing edge of the margins. The applicant has developed a technique that eliminates the need for such a binding.

SUMMARY OF THE INVENTION

[0005] In a broad aspect, then, the present invention relates to a fitted sheet for a mattress comprising a rectangular panel of knit material having a central rectangular area extending from one end of said panel to the other end thereof, and side margins flanking said central area, said side margins being folded under said central area and joined thereto by seams extending across each end of said central rectangular area, characterized in that said seams at each end of said central rectangular area are arcuate.

[0006] In another broad aspect, the present invention relates to a fitted sheet for a mattress comprising a rectangular panel of knit material having a central rectangular area extending from one end of said panel to the other end thereof, and side margins flanking said central area, said side margins being folded under said central area and joined thereto by seams extending across each end of said central rectangular area, characterized in that said rectangular panel of knit material has side edges that are not finished, and at the end of said sheet, said seams are sewn directly over said unfinished edges.

[0007] In yet another broad aspect, the present invention relates to a method of making a fitted sheet, comprising the steps of: (i) cutting a predetermined length of a tube of knit fabric; (ii) slitting said length of fabric along its length in a straight line from end to end; (iii) arranging said fabric so that the slit edges of said fabric are folded over onto the main body of said fabric; and (iv) sewing a seam across each end of the fabric, thereby to join the folded-over edges of the fabric to the main body thereof in a folded over state.

[0008] In a further broad aspect, the present invention relates to a method of making a fitted sheet comprising the steps of: (i) cutting a predetermined length of a tube of knit fabric; (ii) slitting said tube of fabric along an edge thereof, from end to end; (iii) cutting a shallow corner from each end of said tube of fabric, at the slit side thereof, from first points on the cut edge near the end, to second points on the end, near the folded-over mid-line of the slit tube of fabric; (iv) opening the fabric, and folding the side margins thereof inwardly so that at each corner thereof, the said first points are laid on top of the said second points; and (v) sewing a seam across the top and bottom ends of the fabric, to join the folded-over margins to the main body of the sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In drawings that illustrate the present invention by way of example:

[0010]FIG. 1 is a plan view of a first embodiment of the present invention;

[0011]FIG. 1A is an alternative embodiment of the sheet of FIG. 1;

[0012]FIG. 2 is a plan view of a cutting pattern for a sheet of a second embodiment of the present invention;

[0013]FIG. 3 is a plan view of an opened, unsewn sheet blank cut from the pattern of FIG. 2;

[0014]FIG. 4 is a plan view of a sheet sewn from the blank of FIG. 3;

[0015]FIG. 5 is a sectional view through line V-V in FIG. 4;

[0016]FIG. 6 is a sectional view through line VI-VI in FIG. 4.

DETAILED DESCRIPTION OF THE DRAWINGS

[0017] Referring now to FIG. 1, a sheet 1 is illustrated. It comprises a central panel 2 with margins 3 folded over onto same. As shown in dotted lines, the top edge 4 and bottom edge 5, in a sheet according to known envelope sheet design, are sewn across in transverse lines. These edges may have binding attached for additional strength, if desired. When applied to a mattress, the corners 6 at the ends of the top 4 and bottom edges of the sheet tend to form ears.

[0018] The applicant eliminates the formation of ears in the corners 6 of the envelope sheet 1 by providing arcuate 8 rather than straight end edges, as illustrated. By arcing—or even simply angling from the centre (see FIG. 1a, lines 81)—the end edges, the formation of ears of fabric in each corner of the sheet is eliminated or substantially reduced.

[0019] A cutting pattern for a further form of sheet is shown in FIG. 2. A tube 9 of knit fabric is slit in a lengthwise direction along one edge 10. A cutting line 11 is then established at each end of the slit tube. The cutting line extends from a point 12 near the folded, unslit edge of the tube, to a point 13 on the slit edge, at an angle of from about 5° to about 30°, preferably about 10° from the horizontal.

[0020] Referring now to FIG. 3, after cutting, the result is a sheet blank, shaped generally as a large rectangle with truncated corners. That is, in each corner will be a cut line 11 having an inner end 12 and an outer end 13. As shown in FIG. 4, the outer end 13 is then pulled over to meet the respective inner ends of the cut lines, at each end of the sheet blank and the piece is sewn across the end edge thereby established, with the sewing continuing all the way across each end of the sheet. The cut edges of the sheet blank may then be bound with a continuous loop of binding extending around the entire inner perimeter of the sheet, as is currently done, or as shown in FIGS. 5 and 6, the natural tendency for knit fabric to curl may be utilized to obtain an edge that does not require binding, yet remains free of frays or loose threads. To obtain such an edge, the sewer, when sewing across the folded-over cut lines 11 would normally and conventionally seek to flatten out the outer edge 12, which in knit fabric has a tendency to curl. However, according to the process of the present invention, the sewing machine operator permits outer edge to remain curled under, as it will do naturally, or if necessary, curls it under slightly, which can be done without anything more than rolling same with the thumb and a finger. The curled edge 10 is then laid on inner end 13, and sewn flat thereto, as shown in cross-section in FIG. 5. Shown in FIG. 6 is a cross-section of an unflattened portion of the knit edge. When an edge with a curled in profile as shown in FIG. 6 is stretched, as will happen naturally when the sheet is fitted onto a mattress, the curl tends to tighten, due to matting of the fibres at the inner end of the curls, and this results in an edge which takes on a finished appearance, even though no finishing technique other than sewing it flat as shown in FIG. 5 has been applied to the sheet. A length of binding tape may, if desired, be sewn into the seam at each end of the sheet, for added strength.

[0021] Referring to FIGS. 1 and 4, the present invention also provides, in a preferred embodiment, a loop 14 or a flap of tape, binding, or cloth, extending from the upper seam 8. The function of the feature is to provide a resilient surface to which an alarm or intercom bell may be attached without damaging the knit fabric of the sheet.

[0022] The completed sheet of FIG. 4, when applied to a mattress, is a very good fit, with a substantial saving of material, since a narrower tube of material can be used than for an equivalent envelope sheet, and a reduction in associated trim and labour costs. 

What is claimed is:
 1. A fitted sheet for a mattress comprising a rectangular panel of knit material having a central rectangular area extending from one end of said panel to the other end thereof, and side margins flanking said central area, said side margins being folded under said central area and joined thereto by seams extending across each end of said central rectangular area, characterized in that said seams at each end of said central rectangular area are arcuate.
 2. The sheet of claim 1, further characterized in that said seams are symmetrical about a mid-line of said central area that runs from end to end thereof.
 3. The sheet of claim 2, further characterized in that on each side of said mid-line of said central area, at each end of said sheet, said seam curves downwardly toward a folded side edge of said sheet.
 4. The sheet of claim 3, further characterized in that said seam is flatter near said mid-line, and more convex near said folded side edge of said sheet.
 5. A fitted sheet for a mattress comprising a rectangular panel of knit material having a central rectangular area extending from one end of said panel to the other end thereof, and side margins flanking said central area, said side margins being folded under said central area and joined thereto by seams extending across each end of said central rectangular area, characterized in that said rectangular panel of knit material has side edges that are not finished, and at the end of said sheet, said seams are sewn directly over said unfinished edges.
 6. The sheet of claim 5, further characterized in that said unfinished edge is rolled into a curled edge prior to being sewn flat.
 7. The sheet of claim 6, further characterized in that said rectangular panel of knit material is fabricated from a tube of knit material that has been slit and opened to form a rectangle with cut edges.
 8. The sheet of claim 7, further characterized in that said cut edge, in a finished sheet, is curled under into itself.
 9. A sheet as claimed in claim 1, including a loop or length of material extending from the seam at one end of the sheet.
 10. A method of making a fitted sheet, comprising the steps of: i) cutting a predetermined length of a tube of knit fabric; ii) slitting said length of fabric along its length in a straight line from end to end; iii) arranging said fabric so that the slit edges of said fabric are folded over onto the main body of said fabric; and iv) sewing a seam across each end of the fabric, thereby to join the folded-over edges of the fabric to the main body thereof in a folded over state.
 11. The method of claim 10, wherein said slit edges are sewn to said main body in an unfinished state.
 12. The method of claim 11, wherein said slit edges are curled inwardly before being seamed to said main body of said fabric.
 13. The method of claim 12, wherein said seams are generally convexly arcuate.
 14. A method of making a fitted sheet comprising the steps of: i) cutting a predetermined length of a tube of knit fabric; ii) slitting said tube of fabric along an edge thereof, from end to end; iii) cutting a shallow corner from each end of said tube of fabric, at the slit side thereof, from first points on the cut edge near the end, to second points on the end, near the folded-over mid-line of the slit tube of fabric; iv) opening the fabric, and folding the side margins thereof inwardly so that at each corner thereof, the said first points are laid on top of the said second points; and v) sewing a seam across the top and bottom ends of the fabric, to join the folded-over margins to the main body of the sheet.
 15. The method of claim 14, wherein when said seam is sewn, the cut edge of said fabric is curled in, and sewn flat in the curled-in condition.
 16. A sheet as claimed in claim 2, including a loop or length of material extending from the seam at one end of the sheet.
 17. A sheet as claimed in claim 3, including a loop or length of material extending from the seam at one end of the sheet.
 18. A sheet as claimed in claim 4, including a loop or length of material extending from the seam at one end of the sheet.
 19. A sheet as claimed in claim 5, including a loop or length of material extending from the seam at one end of the sheet.
 20. A sheet as claimed in claim 6, including a loop or length of material extending from the seam at one end of the sheet. 